I would like to be able to redirect Trucks from the Mainstreet into the prison, and with that making delivery bays for different kinds of items possible. I think it could give the prison some more indepth planning.

Now that i think about it, that would result into more sprites... I think it wouldn't be that hard if you use the same system as the patrols... With that every Truck[Type] is defined a special route that can be changed... like assigning heavyarmored or normal troops to patrols, just with more diverityIf no route is set, then it just goes it's normal route like always. Maybe add a miscellaneous route for every Trucktype not yet defined. Also for the sake of less bugs you can make it so if you close the "Truckroute"Interface with a routenot connecting up to the road exit it will revert to default or miscellaneouse [if already defined]. For the sake of people who don't want to deal with it we can make it part of the newly added "Logistics"-Unlock.

After writing all this i noticed what exactly your problem was... This could certainly turn into a problem...The only thing i could think of is above mentioned system or special tiles that the trucks would follow, like visitors that only walk on the tiles but not on the road...But there's certainly a way that is easy to use and creative and i believe, that the developers could come up with something... or just use ideas above that are certainly easy...

Oooohhhh my God YES PLEASE! I did not know this was not yet a thing... and burned something like $10k on a nice pretty road coming into my prison and everything... Thankfully I had Forestry up and running already so my workers and 2 gardeners are sitting there making me money hand over fist... but now that big long pretty road I built is completely useless as the driver and workers just walk everything from the trucks to the deliveries section... and I built this on a LARGE scale map too so they have to walk like 40+ squares just to get to deliveries and reception and then walk BACK 40 more! Slowed my progression WAY down. :-/